CN210609056U - Photovoltaic inverter - Google Patents
Photovoltaic inverter Download PDFInfo
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- CN210609056U CN210609056U CN201921765899.0U CN201921765899U CN210609056U CN 210609056 U CN210609056 U CN 210609056U CN 201921765899 U CN201921765899 U CN 201921765899U CN 210609056 U CN210609056 U CN 210609056U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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Abstract
The embodiment of the utility model discloses photovoltaic inverter. The photovoltaic inverter includes: the direct current input end, the direct current filter circuit, the first switch, the direct current conversion circuit, the inverter circuit, the controller and the alternating current output end; a direct current filter circuit and a direct current conversion circuit are sequentially connected between the direct current input end and the inverter circuit, and the inverter circuit is connected with the alternating current output end; a first switch is connected in series on a branch circuit of each direct current conversion circuit connected with the corresponding direct current input end; the controller is electrically connected with the first switch, the direct current conversion circuit and the inverter circuit, and is used for controlling the direct current conversion circuit and the inverter circuit to work and controlling the first switch to be switched on or switched off so as to connect or disconnect the direct current input end and the direct current conversion circuit. The utility model discloses technical scheme has realized automated inspection and has controlled photovoltaic inverter's operating condition, and when photovoltaic inverter broke down, in time break off the photovoltaic cell board of direct current input and direct current conversion circuit's being connected.
Description
Technical Field
The embodiment of the utility model provides a relate to photovoltaic power generation technical field, especially relate to a photovoltaic inverter.
Background
The photovoltaic inverter is widely applied to photovoltaic power generation, and can convert direct current output by a photovoltaic cell panel into alternating current and output the alternating current to a power grid or store the alternating current.
When a circuit is detected to have a problem, for example, an arc discharge fault or an overcurrent fault exists on a direct current side, an existing photovoltaic inverter can immediately block a Pulse Width Modulation (PWM) wave to turn off a switching tube in a direct current circuit, and simultaneously disconnect the direct current side from an alternating current side, so that protection is realized. However, a direct-current side circuit of the photovoltaic inverter is still connected with the photovoltaic cell panel, so that potential safety hazards exist, the photovoltaic inverter is short-circuited, and the photovoltaic cell panel, a cable and the like are damaged.
In the prior art, manual mechanical switches are respectively connected in series with the positive input end and the negative input end of each direct current conversion circuit of the photovoltaic inverter to control the direct current side circuit to be connected with the photovoltaic cell panel, when the photovoltaic inverter comprises a plurality of direct current conversion circuits, the number of the switches in the circuit is too many, manual control is needed, the circuit is difficult to protect in time when the circuit breaks down, the design complexity of the photovoltaic inverter is increased, and the labor cost is wasted.
SUMMERY OF THE UTILITY MODEL
The utility model provides a photovoltaic inverter to automated inspection and control photovoltaic inverter's operating condition, when photovoltaic inverter broke down, in time break off the photovoltaic cell board of direct current input and direct current converting circuit's being connected, simplified photovoltaic inverter's circuit design.
In a first aspect, an embodiment of the present invention provides a photovoltaic inverter, including: the direct current input end, the direct current filter circuit, the first switch, the direct current conversion circuit, the inverter circuit, the controller and the alternating current output end;
the direct current filter circuit and the direct current conversion circuit are sequentially connected between the direct current input end and the inverter circuit, and the inverter circuit is connected with the alternating current output end;
the number of the direct current input ends and the number of the direct current conversion circuits are multiple, and a first switch is connected in series on a branch circuit of each direct current conversion circuit connected with the corresponding direct current input end;
the controller is electrically connected with the first switch, the direct current conversion circuit and the inverter circuit, and is used for controlling the direct current conversion circuit and the inverter circuit to work and controlling the first switch to be switched on or switched off so as to connect or disconnect the direct current input end and the direct current conversion circuit.
Optionally, the first switch is a relay or a contactor.
Optionally, the dc conversion circuit is a dc boost circuit, a dc buck circuit, or a dc buck-boost circuit.
Optionally, the dc conversion circuit includes one dc conversion sub-circuit, or at least two dc conversion sub-circuits connected in parallel.
Optionally, when the dc input terminal includes a positive input terminal and a negative input terminal, and the dc conversion circuit includes a dc conversion sub-circuit, the first switch is connected in series between the positive input terminal and the dc conversion sub-circuit, or the first switch is connected in series between the negative input terminal and the dc conversion sub-circuit.
Optionally, at least two of the dc conversion sub-circuits share a positive electrode or a negative electrode in parallel, and the first switch is connected in series between the dc input terminal and the positive electrode, or the first switch is connected in series between the dc input terminal and the negative electrode.
Optionally, the dc conversion sub-circuit includes: the circuit comprises a first inductor, a first switch tube, a second switch tube, a third switch tube and a first capacitor;
the first end of the first inductor is electrically connected with the first end of the first switch tube, the second end of the first inductor is electrically connected with the first end of the second switch tube and the first end of the third switch tube, the second end of the first switch tube is electrically connected with the second end of the second switch tube and the inverter circuit, the second end of the third switch tube is electrically connected with the inverter circuit, the control end of the third switch tube is electrically connected with the controller, the first end of the first capacitor is electrically connected with the second end of the second switch tube, the second end of the first capacitor is electrically connected with the second end of the third switch tube, the first capacitor is electrically connected with the inverter circuit, and the first end of the first inductor or the second end of the third switch tube is electrically connected with the first switch.
Optionally, the dc conversion sub-circuit further includes a second capacitor, a first end of the second capacitor is electrically connected to the second end of the second switching tube and the first end of the first capacitor, and a second end of the second capacitor is electrically connected to the second end of the third switching tube and the second end of the first capacitor.
Optionally, a soft start circuit is disposed between the dc input terminal and the dc conversion circuit, or between the dc conversion circuit and the ac output terminal.
Optionally, the soft start circuit includes a first resistor connected in series with the first switch in a branch connecting the dc input terminal and the dc conversion circuit.
The embodiment of the utility model provides a photovoltaic inverter, including direct current input end, direct current filter circuit, first switch, direct current converting circuit, inverter circuit, controller and alternating current output, operating condition through controller control direct current converting circuit and inverter circuit, through the closed DC input end and direct current converting circuit of connecting of controller control first switch, or control first switch turn-off with disconnection direct current input end and direct current converting circuit, direct current side circuit still is connected with photovoltaic cell panel and has the potential safety hazard when having alleviated current photovoltaic inverter fault operation, cause the technical problem that photovoltaic inverter damaged, the operating condition of having realized automated inspection and control photovoltaic inverter, when photovoltaic inverter breaks down, in time break off the photovoltaic cell panel and the direct current converting circuit's of direct current input be connected. And the technical scheme of this embodiment simple structure not only can realize automatic control, has practiced thrift the human cost, has reduced manufacturing cost moreover.
Drawings
Fig. 1 is a schematic diagram of a module structure of a photovoltaic inverter according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a module structure of another photovoltaic inverter according to an embodiment of the present invention;
fig. 3 is a schematic circuit structure diagram of a photovoltaic inverter according to an embodiment of the present invention;
fig. 4 is a schematic circuit structure diagram of another photovoltaic inverter according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic diagram of a module structure of a photovoltaic inverter according to an embodiment of the present invention. As shown in fig. 1, the photovoltaic inverter 6 includes: the device comprises a direct current input end A1, a direct current filter circuit 1, a first switch 2, a direct current conversion circuit 3, an inverter circuit 4, a controller 5 and an alternating current output end A2;
a direct current filter circuit 1 and a direct current conversion circuit 3 are sequentially connected between the direct current input end A1 and the inverter circuit 4, and the inverter circuit 4 is connected with an alternating current output end A2;
the number of the direct current input ends A1 and the number of the direct current conversion circuits 3 are multiple, and a first switch 2 is connected in series on a branch circuit of each direct current conversion circuit 3 connected with the corresponding direct current input end A1;
the controller 5 is electrically connected with the first switch 2, the direct current conversion circuit 3 and the inverter circuit 4, and the controller 5 is used for controlling the direct current conversion circuit 3 and the inverter circuit 4 to work and controlling the first switch 2 to be switched on or switched off so as to connect or disconnect the direct current input end A1 and the direct current conversion circuit 3.
Specifically, direct current input A1 can access photovoltaic cell board, provide DC power supply for this photovoltaic inverter 6, ripple among the photovoltaic cell board output voltage can be filtered to direct current filter circuit 1, the direct current of keeping the photovoltaic cell board output and exporting to direct current converting circuit 3, direct current converting circuit 3 can convert the direct current of photovoltaic cell board output into the direct current that satisfies photovoltaic inverter 6's output electric energy demand and export to inverter circuit 4, inverter circuit 4 can convert the direct current of direct current converting circuit 3 output into the alternating current that satisfies the output demand, export to the electric wire netting or save through AC output end A2.
The controller 5 may be configured to control the operation modes of the dc conversion circuit 3 and the inverter circuit 4, for example, may control the period and frequency of the output voltage of the dc conversion circuit 3 and the inverter circuit 4, and the controller 5 may further control the first switch 2 to be closed to keep the dc input terminal a1 connected to the dc conversion circuit 3, or control the first switch 2 to be closed to disconnect the dc input terminal a1 from the dc conversion circuit 3.
This photovoltaic inverter 6 can be applied to photovoltaic power generation, converts the direct current of photovoltaic cell board output into the alternating current that satisfies the demand to can protect photovoltaic power generation system, exemplarily, this photovoltaic inverter 6's theory of operation is: after the photovoltaic inverter 6 is connected to the photovoltaic cell panel through the direct current input end a1, the controller 5 may continuously sample the voltage and current on each branch in the photovoltaic inverter 6 to monitor the working state of the photovoltaic inverter 6 in real time, and if the controller 5 detects that a fault condition such as arc discharge, overcurrent or short circuit occurs in the circuit between the direct current input end a1 and the direct current conversion circuit 3, the controller may immediately control the first switch 2 to be turned off to disconnect the connection between the direct current conversion circuit 3 on the direct current side and the photovoltaic cell panel, so as to prevent the damage of the circuit and the cable inside the photovoltaic cell panel and the photovoltaic inverter 6 caused by the fault, thereby generating a potential safety hazard; if the controller 5 detects that the circuit of the photovoltaic inverter 6 operates normally, the first switch 2 is kept in a closed state to ensure that the photovoltaic inverter 6 operates normally.
Fig. 1 shows only a case where the photovoltaic inverter 6 includes two dc conversion circuits 3, and as shown in fig. 1, when the number of the dc conversion circuits 3 is two, the first switch 2 is connected in series to each of the branches of the dc conversion circuits 3 connected to the dc input terminal a 1. During practical application, can combine particular case to select direct current converting circuit 3's number to set up corresponding direct current input A1, direct current filter circuit 1 and first switch 2, the embodiment of the utility model provides a do not restrict to this.
Illustratively, when the photovoltaic inverter 6 is connected to a plurality of groups of photovoltaic cell panels, the photovoltaic inverter 6 may be correspondingly provided with a plurality of dc input terminals a1, one side of each dc input terminal a1 is connected to a corresponding photovoltaic cell panel, the other side is connected to the dc filter circuit 1, the first switch 2 and the dc conversion circuit 3 in sequence, the output terminal of each dc conversion circuit 3 is electrically connected to the inverter circuit 4, therefore, when the number of the photovoltaic cell panels is large, the direct current can be respectively converted through the multi-path direct current conversion circuit 3, and a first switch 2 is provided between each dc conversion circuit 3 and the corresponding dc input terminal a1, when a fault occurs, the controller 5 can respectively control each first switch 2 to be turned off, so that the direct current conversion circuit 3 of the fault branch circuit is disconnected with the corresponding direct current input end A1, and potential safety hazards are avoided.
The embodiment of the utility model provides a photovoltaic inverter, including the direct current input, direct current filter circuit, first switch, direct current converting circuit, inverter circuit, controller and alternating current output, operating condition through controller control direct current converting circuit and inverter circuit, through the closed DC input and direct current converting circuit of connecting of first switch of controller control, or control first switch turn-off with disconnection direct current input and direct current converting circuit, direct current side circuit still is connected with photovoltaic cell panel and has the potential safety hazard when having alleviated current photovoltaic inverter fault operation, cause the technical problem that photovoltaic inverter damaged, the operating condition of automatic detection and control photovoltaic inverter has been realized, when photovoltaic inverter breaks down, in time break off the photovoltaic cell panel of direct current input and direct current converting circuit's being connected. And the technical scheme of this embodiment simple structure not only can realize automatic control, has practiced thrift the human cost, has reduced manufacturing cost moreover.
Referring to fig. 1, alternatively, on the basis of the above technical solution, the first switch 2 may be provided as a relay or a contactor. For example, when the first switch 2 is a relay or a contactor, the controller 5 may control the relay or the contactor to open a contact of the relay or the contactor to disconnect the dc input terminal a1 from the dc conversion circuit 3 when detecting that the branch current of the relay or the contactor is greater than the preset value and there is an overcurrent fault.
As shown in fig. 1, alternatively, based on the above technical solution, the dc conversion circuit 3 may be a dc boost circuit, a dc buck circuit, or a dc boost-buck circuit. Specifically, the specific values of the output voltage of the photovoltaic cell panel connected to the dc input terminal a1 of the photovoltaic inverter 6 and the output voltage of the ac output terminal a2 may be combined to determine that the dc conversion circuit 3 is used for voltage boosting or voltage reduction, and then the dc conversion circuit 3 is set to be a dc voltage boosting circuit, a dc voltage reducing circuit, or a dc voltage boosting and reducing circuit.
Illustratively, the dc boost circuit may be a switching dc boost circuit, such as a boost circuit, the dc buck circuit may be a buck circuit, and the dc buck circuit may be a buck-boost circuit, and the controller 5 may control a switching tube in the dc boost circuit to turn on or off to control an inductor or a capacitor to store or release energy, so that the output voltage of the dc conversion circuit 3 is lower or higher than the input voltage.
Fig. 2 is a schematic diagram of a module structure of another photovoltaic inverter according to an embodiment of the present invention; fig. 3 is a schematic circuit structure diagram of a photovoltaic inverter according to an embodiment of the present invention; fig. 4 is a schematic circuit structure diagram of another photovoltaic inverter according to an embodiment of the present invention. Referring to fig. 2 to 4, alternatively, on the basis of the above technical solution, the dc conversion circuit 3 may include one dc conversion sub-circuit 31, or at least two dc conversion sub-circuits 31 connected in parallel. Illustratively, the dc conversion circuit 3 may be configured to include one dc conversion sub-circuit 31 (see fig. 2) or a plurality of dc conversion sub-circuits 31 (see fig. 3-4) connected in parallel with each other, in combination with the magnitude of the input power of the photovoltaic inverter 6, and the internal structure of the dc conversion circuit 3 and the magnitude of the output voltage thereof, where the dc conversion sub-circuit 31 may be a boost circuit, a buck voltage reducing circuit, or a buck-boost circuit.
Alternatively, referring to fig. 2, on the basis of the above technical solution, it may be provided that the dc input terminal a1 includes a positive input terminal a11 and a negative input terminal a12, and when the dc conversion circuit 3 includes one dc conversion sub-circuit 31, the first switch 2 is connected in series between the positive input terminal a11 and the dc conversion sub-circuit 31, or the first switch 2 is connected in series between the negative input terminal a12 and the dc conversion sub-circuit 31.
Fig. 2 shows a case where the first switch 2 is connected in series between the negative input terminal a12 and the dc conversion sub-circuit 31, and illustratively, the positive input terminal a11 and the negative input terminal a12 are respectively connected to the positive power terminal and the negative power terminal of the photovoltaic panel 7, so that the photovoltaic panel 7 can be automatically disconnected from the dc conversion circuit 3 when a circuit fault occurs by only providing one first switch 2.
As shown in fig. 3-4, the photovoltaic inverter 6 may be connected to a plurality of photovoltaic cell panels 7, and accordingly, the photovoltaic inverter 6 may include a plurality of positive input terminals a11 and negative input terminals a12, which are respectively used for connecting to a power positive electrode and a power negative electrode of the corresponding photovoltaic cell panel 7, the dc filter circuit 1 may include a filter capacitor C1, the dc output by the photovoltaic cell panel 7 is input to the dc conversion circuit 3 through the dc interface circuit 8 after being filtered by the filter capacitor C1 to perform dc conversion, and then is converted into ac required by the power grid or energy storage through the inverter circuit 4, and is output through the ac output circuit 9, and fig. 3-4 take the three-phase ac output by the photovoltaic inverter 6 as an example, and ac output terminals a21, a22, and a23 are correspondingly provided for outputting electric energy to the power grid or energy storage application.
Optionally, referring to fig. 3-4, on the basis of the above technical solution, the dc conversion circuit 3 may further include at least two dc conversion sub-circuits 31 connected in parallel, where the at least two dc conversion sub-circuits 31 are connected in parallel with a common positive electrode or a common negative electrode, and the first switch 2 is connected in series between the dc input terminal a1 and the common positive electrode, or the first switch 2 is connected in series between the dc input terminal a1 and the common negative electrode.
Fig. 3 shows a case where the dc conversion circuit 3 includes two dc conversion sub-circuits 31 connected in parallel with a common negative electrode, and exemplarily, as shown in fig. 3, taking the first switch 2 as the relay K1 as an example, the relay K1 may be disposed between the dc input terminal a1 and the common negative electrode of the two dc conversion sub-circuits 31, so that the multiple dc conversion sub-circuits 31 can be simultaneously controlled to be connected to or disconnected from the dc input terminal a1 by only one relay K1, and the structure is simple, convenient to control, and low in cost.
For example, fig. 4 shows a case where the dc conversion circuit 3 includes two dc conversion sub-circuits 31 having common anodes connected in parallel, and as shown in fig. 4, a relay K1 may be provided between the dc input terminal a1 and the common anodes of the two dc conversion sub-circuits 31, so that the multiple dc conversion sub-circuits 31 can be simultaneously controlled to be connected to or disconnected from the dc input terminal a1 by only one relay K1.
It should be noted that fig. 3-4 only show the case that the dc conversion circuit 3 includes two dc conversion sub-circuits 31 connected in parallel, and in practical applications, the dc conversion circuit 3 may include a plurality of dc conversion sub-circuits 31 connected in parallel with a common positive electrode or a common negative electrode, and it is sufficient to ensure that the first switch 2 is disposed between the dc input terminal a1 and the common positive electrode or the common negative electrode of the plurality of dc conversion sub-circuits 31.
Optionally, referring to fig. 3, on the basis of the foregoing technical solution, the dc conversion sub-circuit 31 may include: the circuit comprises a first inductor L1, a first switch tube D1, a second switch tube D2, a third switch tube Q1 and a first capacitor C2;
a first end h1 of the first inductor L1 is electrically connected to a first end e1 of the first switching tube D1, a second end h2 of the first inductor L1 is electrically connected to a first end f1 of the second switching tube D2 and a first end g1 of the third switching tube Q1, a second end e2 of the first switching tube D1 is electrically connected to a second end f2 of the second switching tube D2 and the inverter circuit 4, a second end g2 of the third switching tube Q2 is electrically connected to the inverter circuit 4, a control end g2 of the third switching tube Q2 is electrically connected to the controller 5, a first end i2 of the first capacitor C2 is electrically connected to a second end f2 of the second switching tube, a second end i2 of the first capacitor C2 is electrically connected to a second end g2 of the third switching tube, the first capacitor C2 is electrically connected to the inverter circuit 4, and the first end h2 of the first inductor L2 or the second end g2 of the first switch Q2 is electrically connected to the second end g 362.
Illustratively, the operation principle of the dc conversion sub-circuit 31 is as follows: the controller 5 controls the third switching tube Q1 to be periodically turned on or off, when the third switching tube Q1 is turned on, the dc voltage input by the photovoltaic cell panel 7 can charge the first inductor L1, so that the current on the first inductor L1 linearly increases at a certain ratio, the ratio is related to the parameter of the first inductor L1, and as the current of the first inductor L1 increases, the first inductor L1 stores electric energy and provides dc power for the inverter circuit 4; when the third switching tube Q1 is turned off, since the current of the first inductor L1 cannot suddenly change, the first inductor L1 slowly releases the electric energy through the second switching tube D2, and stores the electric energy in the first capacitor C2, the voltage across the first capacitor C2 rises and is higher than the input voltage of the dc converter sub-circuit 31, and at the same time, the dc power supply continues to be provided to the inverter circuit 4, so that the third switching tube Q1 is controlled by the controller 5 to be periodically turned on or off, so that the dc converter sub-circuit 31 can continuously output the electric energy, and the output voltage of the dc converter sub-circuit 31 is higher than the input voltage.
The first switch tube D1 and the second switch tube D2 may be configured to keep the current of the corresponding branch in the dc conversion sub-circuit 31 conducting in the forward direction, so as to prevent the first capacitor C2 from conducting and discharging in the reverse direction through the dc conversion sub-circuit 31 when the dc conversion sub-circuit 31 is disconnected from the dc input terminal a1, and the third switch tube D3 may be configured to protect the third switch tube Q1.
As shown in fig. 3, when the common negative electrodes of the dc conversion sub-circuits 31 are connected in parallel, the second terminal g2 of the third switching tube Q1 may be the common negative electrodes of the two dc conversion sub-circuits 31, and then the first switch 2 may be electrically connected to the dc input terminal a1 and the second terminal g2 of the third switching tube Q1, and the controller 5 controls the relay K1 to close or close, so that the two dc conversion sub-circuits 31 and the dc input terminal a1 may be connected or disconnected. If the dc conversion sub-circuits 31 are connected in parallel with each other in common and the first terminal h1 of the first inductor L1 can be the common anode of the two dc conversion sub-circuits 31, the first switch 2 can be disposed to be electrically connected to the dc input terminal a1 and the first terminal h1 of the first inductor L1.
Optionally, referring to fig. 3, on the basis of the above technical solution, the dc conversion sub-circuit 31 may further include a second capacitor C3, a first end j1 of the second capacitor C3 is electrically connected to a second end f2 of the second switching tube D2 and a first end i1 of the first capacitor C2, and a second end j2 of the second capacitor C3 is electrically connected to a second end g2 of the third switching tube Q1 and a second end i2 of the first capacitor C2. For example, as shown in fig. 3, the dc power in the dc conversion sub-circuit 31 may be filtered by the second capacitor C3 and then input into the first capacitor C2 for storage, so as to filter the ripple component of the voltage in the dc conversion sub-circuit 31.
As shown in fig. 3-4, alternatively, on the basis of the above technical solution, the default state of the relay K1 may be set to be a closed state, and when the controller 5 detects that the photovoltaic inverter 6 has a fault, the relay K1 is controlled to be in a closed state by the controller 5, so as to disconnect the photovoltaic cell panel 7 from the dc conversion circuit 3.
Optionally, on the basis of the above technical solution, a default state of the relay K1 may be set to be an off state, when the controller 5 detects that the photovoltaic inverter 6 starts to operate, the relay K1 is controlled to be in the on state, and if it detects that the photovoltaic inverter 6 fails, the relay K1 is controlled to be in the off state by the controller 5, so as to disconnect the photovoltaic cell panel 7 from the dc conversion circuit 3.
As shown in fig. 3, alternatively, on the basis of the above technical solution, when the default state of the relay K1 is the off state, a soft start circuit may be provided between the dc input terminal a1 and the dc conversion circuit 3, or between the dc conversion circuit 3 and the ac output terminal a 2. Illustratively, since the default state of the relay K1 is an off state, when the photovoltaic inverter 6 is started to start working, the relay K1 needs to be controlled to be closed, and the soft start circuit is arranged to reduce the impact current caused when the relay K1 is closed.
Alternatively, as shown in fig. 3, on the basis of the above technical solution, the soft start circuit may include a first resistor R1, and the first resistor R1 is connected in series with the first switch 2 in the branch connecting the dc input terminal a1 and the dc conversion circuit 3. Specifically, the first resistor R1 may be a current limiting resistor for reducing a rush current caused when the relay K1 is closed, and preventing a circuit in the photovoltaic inverter 6 from being damaged.
Optionally, on the basis of the above technical solution, the soft start circuit may also include a first resistor R1, and the first resistor R1 is connected in parallel with the relay K1, so that the first resistor R1 can share a part of the inrush current caused when the relay K1 is closed, and the circuit in the photovoltaic inverter 6 is prevented from being damaged.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (10)
1. A photovoltaic inverter, comprising: the direct current input end, the direct current filter circuit, the first switch, the direct current conversion circuit, the inverter circuit, the controller and the alternating current output end;
the direct current filter circuit and the direct current conversion circuit are sequentially connected between the direct current input end and the inverter circuit, and the inverter circuit is connected with the alternating current output end;
the number of the direct current input ends and the number of the direct current conversion circuits are multiple, and a first switch is connected in series on a branch circuit of each direct current conversion circuit connected with the corresponding direct current input end;
the controller is electrically connected with the first switch, the direct current conversion circuit and the inverter circuit, and is used for controlling the direct current conversion circuit and the inverter circuit to work and controlling the first switch to be switched on or switched off so as to connect or disconnect the direct current input end and the direct current conversion circuit.
2. The pv inverter of claim 1, wherein the first switch is a relay or a contactor.
3. The pv inverter of claim 1, wherein the dc conversion circuit is a dc boost circuit, a dc buck circuit, or a dc buck-boost circuit.
4. The pv inverter of claim 1, wherein the dc conversion circuit comprises one dc conversion sub-circuit or at least two parallel dc conversion sub-circuits.
5. The pv inverter of claim 4 wherein the dc input comprises a positive input and a negative input, and wherein the dc conversion circuit comprises a dc conversion sub-circuit, and wherein the first switch is connected in series between the positive input and the dc conversion sub-circuit, or wherein the first switch is connected in series between the negative input and the dc conversion sub-circuit.
6. The pv inverter of claim 4 wherein at least two of the dc conversion sub-circuits are connected in parallel with a common positive or common negative pole, and wherein the first switch is connected in series between the dc input and the common positive pole, or wherein the first switch is connected in series between the dc input and the common negative pole.
7. The photovoltaic inverter of claim 6, wherein the DC conversion sub-circuit comprises: the circuit comprises a first inductor, a first switch tube, a second switch tube, a third switch tube and a first capacitor;
the first end of the first inductor is electrically connected with the first end of the first switch tube, the second end of the first inductor is electrically connected with the first end of the second switch tube and the first end of the third switch tube, the second end of the first switch tube is electrically connected with the second end of the second switch tube and the inverter circuit, the second end of the third switch tube is electrically connected with the inverter circuit, the control end of the third switch tube is electrically connected with the controller, the first end of the first capacitor is electrically connected with the second end of the second switch tube, the second end of the first capacitor is electrically connected with the second end of the third switch tube, the first capacitor is electrically connected with the inverter circuit, and the first end of the first inductor or the second end of the third switch tube is electrically connected with the first switch.
8. The pv inverter of claim 7, wherein the dc conversion sub-circuit further comprises a second capacitor, a first terminal of the second capacitor is electrically connected to the second terminal of the second switching transistor and the first terminal of the first capacitor, and a second terminal of the second capacitor is electrically connected to the second terminal of the third switching transistor and the second terminal of the first capacitor.
9. The pv inverter of claim 1, wherein a soft start circuit is provided between the dc input and the dc conversion circuit or between the dc conversion circuit and the ac output.
10. The pv inverter of claim 9 wherein the soft start circuit includes a first resistor connected in series with the first switch in a branch of the dc input to the dc conversion circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921765899.0U CN210609056U (en) | 2019-10-21 | 2019-10-21 | Photovoltaic inverter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921765899.0U CN210609056U (en) | 2019-10-21 | 2019-10-21 | Photovoltaic inverter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210609056U true CN210609056U (en) | 2020-05-22 |
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| CN116014798A (en) * | 2023-02-01 | 2023-04-25 | 广东首航智慧新能源科技有限公司 | Control circuit, parallel control circuit and energy storage inverter system thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116014798A (en) * | 2023-02-01 | 2023-04-25 | 广东首航智慧新能源科技有限公司 | Control circuit, parallel control circuit and energy storage inverter system thereof |
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